Over 29,000 foreign nationals are detained yearly in British Immigration Removal Centres for undefined periods. This study investigated the role played by social identities in the way detainees are affected by, make sense of, and deal with detention. An opportunity sample of 40 detainees was interviewed on topics including support, identity, and well-being, and data were analysed using theoretical thematic analysis. Participants struggled with loss of social networks, loss of rights, loss of agency, and joining a stigmatised group. Social identities guided exchange of support, aided meaning-making, and mitigated distrust, serving as 'Social Cures'. However, shared identities could also be sources of burden, ostracism, and distress, serving as 'Social Curses'. Inability to maintain existing identities or create new ones fuelled feelings of isolation. Participants also reported rejection/ avoidance of social identities to maximise their benefits. This study is the first to apply the Social Identity Approach to the experience of immigration detention.